DE102011012603A1 - Permanently meshed starter with a dry freewheel - Google Patents

Abstract

Dry freewheel for a permanently engaged starter with a flange coupled to the crankshaft / primary mass, a ring gear coupled to the starter shaft and a cage on which several spring-loaded clamping bodies are received, which in the coupled state are connected to a drive plate connected to the ring gear ( Outer ring) and flange (inner ring) act and transmit a torque between the drive plate and the flange and which are separated from the drive plate in the uncoupled state (idle), the springs being compression springs according to the invention.

Description

The invention relates to a permanently starter starter with a dry freewheel and is used in particular in internal combustion engines and serves to decouple crankshaft or primary mass and starter ring gear during operation by the freewheel. The freewheel works in such a way that it transmits the speed between crankshaft or primary mass and starter ring gear or starter shaft up to a certain moment and no torque is transmitted at an increasing moment.

A starter freewheel for an electric starting device for internal combustion engines for temporarily coupling the starter shaft with the crankshaft is also off DE 100 19 593 A1 known. The starter clutch comprises an inner ring coupled to the crankshaft, an outer ring coupled to the starter shaft and sprags effective for startup operation for frictional engagement of the two rings and a cage for the sprags and means for friction or positive engagement of the cage with the inner ring. In overtaking the clamp body are pivoted under the action of centrifugal force such that they are separated from the outer ring. The clamping body are pivotally mounted with leaf springs in a cage support ring.

It has already been attempted to provide the freewheel with means that support the clamp body in the decoupled state. The clamp bodies are fastened to the cage by means of a helical spring.

The clamping body of a freewheel can also be acted upon by means of a leg spring.

A disadvantage of these systems is that the prestressing of the clamping bodies takes place via installation-consuming and / or strength-critical springs, whereby a high number of parts which assume different functions (centering, spring installation, and the like) is required. Another disadvantage is that it can come by the springs used to oscillations of the clamping body by the sometimes very high centrifugal forces acting on the clamp body, which has an overall negative effect on the life of the freewheel.

The object of the invention is the construction of a dry freewheel, which is easy to install and robust and has a reduced number of parts, the component wear and noise is low and the structural design ensures that the torque flow from the starter to the engine as soon as the engine automatically runs, is interrupted and the restart of the engine below a limit speed is possible at any time, for which the clamp body in a defined speed range off or must swing. Furthermore, the cage, in which the clamp body are mounted centered to the crankshaft and at the same time be connected with friction.

For this purpose, the dry freewheel for a permanently starter starter coupled to the crankshaft / the primary mass flange, coupled to the starter shaft sprocket and a cage on which a plurality of spring-biased clamping body are received, on, wherein the clamping body in the coupled state on a connected to the sprocket drive plate (outer ring) and flange (inner ring) act and transmit torque between the drive plate and the flange and in the decoupled state (idle) are spaced from the drive plate, according to the invention, the springs are compression springs.

Advantageously, the compression springs are based on plastic parts and are guided laterally / axially fixed by means of the plastic parts. The plastic parts simultaneously center the cage with respect to the inner ring on the crankshaft.

The cage has two side plates and the plastic parts also cause a clamping of the cage by acting on the side panels of the cage bias.

Preferably, in each case a compression spring bears against the plastic part on the one hand and is connected to the other in particular via a pressure piece with the clamping body, wherein the pressure piece is advantageously rotatably mounted in the clamping body.

When rotating the clamping body, the pressure piece is thereby pivotally mounted, wherein the compression spring is actuated substantially in parallel.

Another function of the two plastic parts is that they prevent slipping out of the compression spring under centrifugal force in the pivoted end position of the clamp body.

The two side panels of the cage are fixedly connected to each other via spacer bolts, on which the clamping bodies are pivotally received. In the two side panels, the plastic parts are fixed, with friction surfaces are located on the plastic parts, which have contact with the flange and thereby frictionally connect the cage to the flange.

The inventive design of the dry freewheel for a eingespurten Starters are reduced in particular by the use of compression spring vibrations and noise and increases the life. Furthermore, the dry freewheel has a robust construction with a small number of parts, which is easy to install.

The invention will be explained in more detail with reference to an embodiment and associated drawings. Show it:

1 the cut by a freewheel,

2 the cut through a cage with plastic parts

3 the detail view of the cage centering,

4 the representation of the clamping mechanism in front view with engaged clamping bodies,

5 the representation of the clamping mechanism in the front view with raised clamping bodies.

In 1 the longitudinal section of the freewheel is shown. The starter not shown here meshes with the sprocket 1 , which with the drive plate 2 is connected as desired. About any camp 3 is the drive disc 2 with the sprocket 1 about the axis A rotatably mounted on the engine, not shown.

A flange 4 is secured against rotation on the crankshaft, also not shown here. The coupling between the flange 4 and the drive disc 2 via any number of clamp body 5 , These jam in the gap between the drive plate and the flange 4 , whereby over the clamping bodies 5 between drive plate 2 and flange 4 a torque is transmitted. This creates a frictional connection between these parts and the starting torque of the starter can be transmitted to the crankshaft.

Rotates the flange 4 faster than the drive plate 2 takes the clamping force of the clamp body 5 from. The freewheel releases as the clamp body 5 no contact with the drive plate 2 have, whereby no moment is transferred any more.

When the freewheel overtakes, there is a relative movement between the flange 4 , the driving disc 2 and the sprags 5 , In order to keep the wear on the aforementioned components low over the life, the clamp body should 5 Turn from a certain speed in the nip and so the direct contact with drive plate 2 and flange 4 to lose. This should be speed dependent.

When the starting process of the internal combustion engine is completed, the flange rotates 4 with the engine speed. The starter stops turning and the drive plate 2 stops too. It is therefore a necessity that the clamping body 5 in some form from the flange 4 be taken to get the necessary for twisting centrifugal force. The function of the coupling of clamping body 5 and flange 4 takes over a cage.

The cage consists of two side plates 6 , which are arranged on both sides of the clamping bodies and spacers over 7 are firmly connected. On the facing inner sides of the side plates 6 are thin-walled plastic parts 8th attached. The representation of the cage with the plastic parts 8th and the sprags 5 will be in the 2 and 3 shown. The plastic parts 8th take over several functions simultaneously. First, they center the entire cage on the flange 4 , on the other hand, are located towards the flange 4 friction surfaces 10 on the two plastic parts 8th , These have contact with the flange 4 and are energized. Thus, the cage is frictional to the flange 4 tethered. The clamping force is achieved by preloading the side plates 6 generated and is arbitrarily adjustable. In the area of the distance bolts 7 form the plastic parts 8th , on both sides of the clamp body 5 are arranged, a lateral guide for the clamp body.

Out 3 it can be seen that the compression spring 13 on the plastic parts 8th by means of plants 12 supported 12 and being centered by them.

The position of the clamp body 5 is by the distance bolt 7 defined to the the clamping body 5 is pivotally mounted.

4 shows the representation of the clamping mechanism in front view with engaged clamping bodies 5 , Because the focus 14 of the clamp body 5 specifically outside the axis of rotation of the clamp body 5 is located, the rotational movement of the internal combustion engine generates a moment which is used to rotate the clamp body 5 leads. A stop bolt 15 defines the end position of this twisting movement. So that the clamping body 5 swings in or out in a certain speed range, is the clamp body 5 through the compression spring 13 biased. About the compression spring 13 as well as the location of the center of gravity 14 and the mass of the clamp body, the Abhebe- or applying speed is defined. The compression spring 13 lies on the one hand with a plant 12 on the plastic part 8th on the other hand it is about a pressure piece 16 with the clamp body 5 connected. The pressure piece 16 is about a storage 17 rotatable in the clamp body 5 stored. So can when turning the clamp body 5 the pressure piece 16 pivot and the compression spring 13 is operated as far as possible in parallel.

The representation of the clamping mechanism in the front view with raised clamping bodies is in 5 shown. In this swung-out end position of the clamp body 5 prevent the two plastic parts 8th and the pressure piece 16 slipping out of the compression spring 13 under centrifugal force.

By the solution according to the invention, on the one hand, the axial displaceability of the clamping body is limited, on the other hand rattling noises are reduced by dynamic vibrations of the clamping body in the unclamped state.

In addition to the lateral guidance of the clamping body, the plastic parts at the same time take over the centering of the cage relative to the inner ring (flange) on the crankshaft and the clamping of the cage. The clamping force is created by preloading the side panels of the cage.

This constructive design ensures that the torque flow from the starter to the engine, as soon as the engine is running automatically, is interrupted and the restart of the engine below a limit speed is possible at any time, for which the clamp body swing in a defined speed range or. Furthermore, the cage in which the clamp body are mounted centered on the crankshaft and connected for the first time with friction.

LIST OF REFERENCE NUMBERS

1

sprocket

2

driver disc

3

camp

4

flange

5

clamping bodies

6

side panels

7

Standoffs

8th

Plastic parts

10

friction surfaces

12

investment

13

compression spring

14

main emphasis

15

stop pin

16

Pressure piece

17

storage

A

axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10019593 A1 [0002]

Claims (10)

Dry freewheel for a permanently interlocked starter with a flange coupled to the crankshaft / primary mass ( 4 ), a ring gear coupled to the starter shaft ( 1 ) and a cage, on which several spring-biased sprags ( 5 ), which in the coupled state at one with the sprocket ( 1 ) associated drive plate ( 2 ) (Outer ring) and flange ( 4 ) (Inner ring) and a torque between the drive plate ( 2 ) and the flange ( 4 ) and in the decoupled state (idle) of the drive plate ( 2 ) are spaced, characterized in that the springs compression springs ( 13 ) are. Freewheel according to claim 1, characterized in that the compression springs ( 13 ) on plastic parts ( 8th ). Freewheel according to claim 1 or 2, characterized in that the clamping body ( 5 ) laterally / axially fixed by means of the plastic parts ( 8th ), at which the compression springs ( 13 ). Freewheel according to one of claims 1 to 3, characterized in that the plastic parts ( 8th ) the cage opposite the flange ( 4 ) center on the crankshaft. Freewheel according to one of claims 1 to 4, characterized in that the cage side plates ( 6 ) and that the plastic parts ( 6 ) a clamping of the cage by a on the side panels ( 6 ) ensure the cage acting bias. Freewheel according to one of claims 1 to 5, characterized in that in each case a compression spring ( 13 ) on the one hand on the plastic part ( 8th ) and on the other hand via a pressure piece ( 16 ) with the clamping body ( 5 ) connected is. Freewheel according to claim 6, characterized in that the pressure piece ( 16 ) rotatable in the clamping body ( 5 ) is stored. Freewheel according to one of claims 1 to 7, characterized in that during rotation of the clamping body ( 5 ) the pressure piece ( 16 ) and the compression spring ( 13 ) is substantially parallel actuated. Freewheel according to one of claims 1 to 8, characterized in that in the pivoted end position of the clamping body ( 5 ) the two plastic parts ( 8th . 16 ) slipping out of the compression spring ( 13 ) under centrifugal force. Freewheel according to one of claims 1 to 9, characterized in that the two side plates ( 6 ) of the cage via spacers ( 7 ) and that in the side panels ( 6 ) the plastic parts ( 8th ), wherein friction surfaces ( 10 ) on the plastic parts ( 8th ), the contact with the flange ( 4 ) and the cage frictionally attached to the flange ( 4 ) connect.

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